<template>
  <div>
    <router-link
    tag="div"
    to="/"
    class="header-abs"
    v-show="showAbs">
      <div class="iconfont header-abs-back">&#xe624;</div>
    </router-link>
    <div 
    class="header-fixd" 
    v-show="!showAbs"
    :style="opacityStyle">
        <router-link to="/">
            <div class="iconfont header-fixd-back">&#xe624;</div>
        </router-link>
        景点详情
    </div>
  </div>
</template>

<script>
export default {
name: 'DetailHeader',
  data () {
      return {
          showAbs: true,
          opacityStyle: 0
      }
  },
  methods: {
      handleScroll : function(){
        const top = document.documentElement.scrollTop
        if (top > 60) {
            let opacity = top / 140;
            opacity > 1 ? 1 : opacity;
            this.opacityStyle = {
                opacity
            }
            this.showAbs = false
        }else {
            this.showAbs = true
        }
      }
  },
  activated () {
      window.addEventListener('scroll',this.handleScroll)
  },
  deactivated() {
    window.removeEventListener('scroll',this.handleScroll)
  }

}
</script>

<style lang="stylus" scoped>
@import '~styles/varibles.styl'
  .header-abs
    position absolute
    left .2rem
    top .2rem
    width .8rem
    height .8rem
    line-height .8rem
    border-radius .4rem
    background rgba(0,0,0,.8)
    text-align center
    .header-abs-back
      color #fff
      font-size .4rem
.header-fixd
  z-index 2
  position fixed
  top 0
  left 0
  left 0
  width 100%
  height: $headerHeight
  line-height $headerHeight
  text-align center
  color #fff
  background: $bgColor
  font-size .32rem
  .header-fixd-back
    position absolute
    top 0
    left 0
    width .64rem
    text-align .4rem
    font-size .4rem
    color #fff
</style>